NEW YORK—According to sources throughout the commercial aviation sector, the nation’s airlines will begin installing awkwardly placed bumps in every airplane seatback this week because it reportedly brings great pleasure to them. “Over the next four to six months, across our entire fleet, we’ll be rolling out seats with an irritating array of lumps and ridges to painfully jab our customers in the back, and we couldn’t be more delighted about it,” said United...